A more thorough explanation:

An iron-safe clause is a provision in a fire-insurance policy that requires the insured to keep their business's books and inventory records in a fireproof safe. This clause is important because it helps to protect important documents from being destroyed in the event of a fire.

For example, let's say that a business owner has a fire-insurance policy that includes an iron-safe clause. The owner must keep their books and inventory records in a fireproof safe to be covered by the policy. If a fire were to occur and the owner did not have their documents stored in a fireproof safe, the insurance company may not cover the loss.

Another example could be a homeowner's insurance policy that includes an iron-safe clause. The homeowner must keep important documents, such as their mortgage papers and insurance policies, in a fireproof safe to be covered in the event of a fire.

These examples illustrate how an iron-safe clause is an important provision in insurance policies that helps to protect important documents from being destroyed in a fire.